Originally Posted by gedster314
What Version were you on when you could not unlock it. And what version did you flash?
I'm not so sure it had much to do with the version, although I am no expert dev. Mind you, this happened in a short period of time.
I was on The stock (shipped) rom when I first bought my GN2. I got it new and broke the seal on the box. Upon opening and starting the device, I got an OTA update (don't remember the build but not the LL4 ota). I started doing some reading on XDA, since like most, I like tinkering and tweaking. Not long after that (Mid Jan 2013) I got the OTA from TMO that had "minor fixes and security changes". This is when I read somewhere on XDA that it is not recommended that we accept the OTA update. But it was too late; I had already done it. I came across the unlock instructions posted earlier in this thread but I couldn't get pass all the steps. A few days later I rooted via ROOT66_TMO_UVALL4 rom, which gave me access to SuperUser. [I have this ZIP saved if anyone wants it and wants to show me how share it.]
Then I got an official unlock code from TMO.
I followed these instructions that TMO sent me with the unlock code
Thank you for taking the time to contact T-Mobile. Below you will see the Instructions for unlocking your Samsung device.
Please be advised a non T-Mobile SIM card MUST be used to unlock this device.
1. Insert a NON T-Mobile SIM & turn Device on
2. The Device will automatically prompt you to enter code into an empty field.
3. Click/Tap in the empty field above the "Unlock & Dismiss" options (this will display a key pad on the screen).
4. Using the key pad input the Unlock Code provided by T-Mobile.
5. Press the Back button to remove the keyboard from screen.
6. Click/Tap the "Unlock" option; handset should display "Network Unlock Successful".
Please note that if you are unlocking a flip device please use steps 1, 2, 3 and 6.
In my haste, I didn't follow the instruction EXACTLY as written. Somehow I managed to enter the unlock code while using my TMO sim and not the "NON TMO sim". When I did this, I got the message in step 6. I thought I was good from here. I tried an ATT sim a few days later to verify but it asked me again for the sim unlock code but the operation was unsuccessful. I tried entering the donor phone's screen unlock code a few times as well as zeros and 1234 and again failed. I tried again with another donor phone with the same result. TMO sent me a second unlock code which also failed. I did tell them that I had done the OTA update and the rep told me it shouldn't matter. I did not tell them I was rooted stock though. The rep told me that due to entering the wrong code multiple times, the device went into "security lockout" and could not be unlocked. I read into several threads and posts and could not find the answer, Thus my original post. I down graded my Rom to T889UVALJ1, successfully performed the unlock procedure posted above (NOT TMO official), and re-installed the ROOT66 rom. Everything is now working perfectly. I put in the ATT sim and it pops right up as ATT.
The real question now is, does the OTA issued by TMO block the unlock exploit and is that what they refer to when they mention "security features"?
Thank for Solving this issue goes to user Pirobo_Colombino see post 2